This invention relates to flexible closure plug mats presenting arrayed pluralities of septa closure plugs for convenient insertion in the open upper ends of corresponding arrayed pluralities of sample vials mounted in well plates for use in chromatography equipment. More particularly, this invention avoids contamination of liquid samples by employing an assembly of a flexible silicone elastomer body having anchored to its underside a relatively thick Teflon(copyright) layer presented to the sample vials"" contents.
Autosampling chromatography equipment marketed by Hewlett-Packard, Perkin-Elmer, Merck/Hitachi and other manufacturers accommodates standard sizes of well plates, such as the 96-vial well plate carrying twelve rows of eight vials each, illustrated in the FIGURES. The wells of these well plates are sized to receive thin-walled glass vials, 5 mm or 6 mm in diameter, for example, to be loaded by pipettes with liquid samples to be analyzed. Once loaded, closure plugs or septa are inserted and secured by crimped metal rims, by screw caps, or by elastomer friction. Closure plugs may be of polyethylene, natural rubber or silicone rubber. Inert outer coatings of polytetrafluoroethylene (PTFE or xe2x80x9cTEFLON(copyright)xe2x80x9d) have been proposed, sprayed or dusted on the surface of such elastomer plugs to minimize contamination of liquid samples in vials, but such sprayed PTFE coatings can be scraped off or degraded during opening and closing operations, and their performance has been unreliable and unpredictable.
it has now been discovered that a thick layer 21 of Teflon(copyright),at least about 0.100 mm or 0.004 inches in thickness, durably bonded at 30 to the lower face of the elastomer septa closure plug mat 22, to be exposed to liquid samples and solvents loaded into the glass vials 23, forms a highly dependable closure system for the entire array of sample vials, minimizing or eliminating contamination of all samples.
A principal object of the invention is therefore to produce elastomer septa closure plug mats 22 for multiple arrays of sample vials 23 mounted in a well plate 24 in standard arrays, eliminating contamination of vial sample contents.
Another object of the invention is to provide such closure plug mats 22 of durably bonded dual layer construction, presenting a permanent inert surface facing the sample contents of the arrayed vials 23.
Other objects of the invention will in part be obvious and will in part appear hereinafter.
The invention accordingly comprises the features of construction, combinations of elements, and arrangements of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.